var fs=require('fs');

var readStream=fs.createReadStream('../../我的家乡 黄海军.pptx');
var writeStream=fs.createWriteStream('1.pptx');

readStream.on('data',function(chunk){
  if(writeStream.write(chunk)==false){
    console.log('still cached');
    readStream.pause()
  }
})

readStream.on('end',function(){
  writeStream.end();
})

writeStream.on('drain',function(){
  console.log('data drains');

  readStream.resume();
})
